Stop mechanism for knitting machines



June '21, 1938. M. WACHSMAN STOP MECHANISM FOR KNITTING MACHINES Filed May 25, 1957 JI L JNVENTOR. 77 /656; flaifmdh BY W T EY Patented June 21, 1938 UNITED-STATES STOP MECHANISM FOR KNITTING.

MACHINES Michael Wachsman, Brooklyn, N. Y. Application May 25, 1937. Serial No. 144,586

1 Glaim.

This invention relates to improvements in stop mechanisms for knitting machines of the general type disclosed in Reissue Patent 19,069, February 6, 1934. Such stop mechanisms are included in an electric stop circuit and .are provided with two yarn supporting levers so arranged that during the normal operation of the knitting machine the yarn keeps the levers in a circuit open position but when a knot occurs in the yarn one of the levers is moved to a circuit closing position and when the yarn breaks another of said levers is moved to close the circuit. The closing of the circuit in either event operates to stop the machine.

Depending upon their function the levers are called knot detectors and end detectors. Springs or counterweights are usually employed to keep the levers in circuit open position. In the present instance springs are used for both levers.

The particular object of this. invention is to provide novel means for attaching the springs to the levers whereby a more delicate and smoother operation of the device is obtained. Specifically one object of the invention is to attach the springs to the levers in such a manner that the springs may be adjusted to a. very fine degree sufficient only to keep the leversin normal position during operation, the adjustment being such that it does not offer any material assistance to the pull or weight of the yarn which is placed upon the levers.

The invention will be more fully understood from the following specification read in connection with the accompanying drawing in which,

Fig. 1 is a side view of the improved stop mechanism with parts insection and parts broken away.

Fig. 2 is a front view with parts broken away.

Fig. 3 is a horizontal sectional View on line 3, 3 of Fig. 1 with parts removed. 7

Fig. l is a sectional View similar to Fig. 1 but showing the yarn supporting levers in moved down position.

Figs. 5 and 6 are detail views showing modifications in the manner of attaching the springs to the levers.

Figs. '7, 8 and 9 illustrate modifications in the forms of the levers and associated parts.

The stop mechanism includes a housing I in which there is supported at 2 a knot detector lever 3 having a yarn supporting porcelain arm member 4. Above the lever 3 there is pivoted at 5 an end detector lever B. The two levers 3 and 6 are adapted to support the yarn or thread 1 as shown. Inside the box I the two levers are formed with contact heels 8 and 9 respectively which are adapted to close the electric circuit in a Well known manner by contact with resilient spring contact fingers l0 and l l which are secured to the housing by a fixed circuit terminal I2 in a well known manner.

The knot detector lever 3 is held in a normal circuit open position against a stop I3 by means of a spring [4 the tension of which is adjustable by a screw I5. The end detector lever 6 has attached thereto inside the housing another spring l6 which is adjustable by a screw ll, the adjustment being such that when the yarn is in position as in Fig. 1 the spring l6 tends to move the knot detector lever upwards to lift the yarn off the knot detector lever and decrease friction and ease the operation. If the yarn breaks or runs out the spring l6 pulls the end detector lever down into contact making position against the contact finger II as will be understood.

When a knot occurs the two levers are pulled down by the yarn as shown in Fig. 4. The yarn slips oil the fingers and the spring I4 will then pull the knot detector lever back into normal position, while the other spring 16 swings the end detector lever upwards. When the yarn is again ready to be used, the operator places it upon both levers which are then again brought into normal position as in Fig. 1.

Heretofore the springs have been attached to the levers at fixed points. I have found that the mechanism will operate to better advantage if the springs are connected to the levers in such a manner that the springs may slide along the lever towards the pivots thereof when the levers are operated by the yarn.

As shown in Fig. 1, the upper ends of the two springs are attached to the levers by means of loops or eyes 2|] which slide freely upon the levers. When a knot occurs the yarn pulls the levers down against the spring tension. If the spring is attached to the lever at a fixed point such as in prior structures, the yarn must itself do all the work in overcoming the tension of the spring. In the present instance as soon as the yarn pulls down the levers, the upper ends of the springs slide towards the lever pivots. Obviously such a movement eases the tension of the springs and the yarn may pull the levers down and slip oif without breaking.

This arrangement is especially advantageous where the machine operates on very fine, very thin yarn or thread, because the springs may be 1 initially adjusted to barely balance or just balance or keep the levers in normal adjusted position against the drag of the thread, but being capable of immediate release by reason of the fact that the springs slide down toward the pivots. The contact heels serve as stops to prevent the springs from becoming detached from the levers.

Fig. 5 shows a'modification in which the spring is attached to a small wheel 30 which runs upon the lever and thus operates more easily than a mere loop. In Fig. 6 the wheel 30 carries also a Weight 3|. Both forms in Figs. 5 and 6 operate without any tendency to bind such as might cc- 0111 with the construction shown in Fig. 1.

Figs. '7 and 8 illustrate a kmot detector lever which has two forward porcelain arms 4. In this form of the invention the knot detector lever 3 is pivoted at 22 in the sides of the box I and has a contact shoe 23 adapted to make contact with a pivoted contact lever 24 as shown. The spring may advantageously be connected to the lever by means of the wheel shown in Fig. 5 or 6.

A still further modification is shown in Fig. 9. Here the double knot detector lever 25 has pivot points 26 and a contact heel 21 which operates like the heel 8 in Fig. 1. In Fig. 9 the spring 28 is attached to a pin 29 which has a sliding engagement with the lever 25. When the lever is pulled down, the pin slides in the lever as is obvious and the spring also in this case moves towards the lever pivot.

I claim:--

In combination a housing, a yarn supporting lever pivoted in the housing and having an arm extending within the same, a spring in thehousing for maintaining the lever in normal yarn supporting position, means for adjustably securing one end of the spring to the housing, a weighted wheel adapted to run upon the said lever arm and means for securing the other end of the spring to the weighted wheel.

MICHAEL WACHSMAN. 

